Moral Imperatives Posed by Existential Risk
25 February 2013
Morally Distinguishable Outcomes in
Global Catastrophic Scenarios
Below is Nick Bostrom’s table of qualitative categories of risk. Bostrom and Milan M. Ćirković have together edited a book on Global Catastrophic Risks, which includes this table. Existential risks, that is to say, risk that could result in human extinction, are identified as “an especially severe subset” of global catastrophic risks.
Of existential risks and their potential consequences I recently wrote this:
“When we think about what this means for us, our other ‘priorities’ pale by comparison. Nothing else matters, no matter how apparently pressing, if we are made extinct by an accident of local cosmology.”
Thinking of this further, I realized that there are many ethical presuppositions implicit in my formulation, and that (at least some of) these presuppositions can be spelled out and made explicit.
Bostrom’s table of qualitative risk categories suggest possibilities of scope and intensity beyond those comprised by global catastrophic risk and existential risk, and on the margin of the table we see “Cosmic?” as a possible scope beyond “pan-generational” and “Hellish?” as a potential intensity beyond “Terminal.” Thus what is cosmic and hellish is a qualitative risk category beyond even that of existential risk. I think that there are moral intuitions from catastrophic outcomes that correspond to these almost unthinkable scenarios.
While it would seem that there is little worse that could happen (from a human perspective, i.e., fully informed by anthropic bias) than human extinction, even given our anthropic bias and therefore our desire to avoid human extinction there are morally distinguishable outcomes in many different scenarios of global catastrophe and human extinction, and where there is the possibility of morally distinguishable outcomes there also will be the possibility of ranking these moral outcomes from the least awful possibility to the worst of all possibilities. There is also the likelihood of moral disagreements on these rankings, and these moral disagreements over prioritizing existential risk mitigation could prove crucial in future debates over the allocation of civilizational resources to existential risk mitigation. Thus even if existential risk comes to be seen as an overriding priority for human beings and civilization, this is not yet the convergence of human moral effort; room for profound disagreement yet remains.
Considering a range of devastating and catastrophic events that could compromise human life and human civilization, possibly to the point of their extinction, I can think of six scenarios in order of severity:
1. Massive but survivable catastrophe A global catastrophic risk realized that results in the loss of millions or billions of lives and deals a major setback to civilization, without either extinguishing human beings or human civilization (in Bostrom’s table of qualitative risks these would include global, trans-generational, and pan-generational endurable risks).
2. Catastrophic failure of civilization A global catastrophic risk realized that resulted in the catastrophic failure of civilization, but does not result in the extinction of human beings. The human population might be drastically reduced to paleolithic population levels, but potentially could rebound. There remains the possibility that civilization might be reconstituted, but this is likely to take hundreds if not thousands of years. (“Global dark age” in the table above.)
3. Human extinction The first level of human extinction I will call simple extinction, which is an existential risk realized, which however leaves the Earth intact, and the legacy of human civilization intact. I add this latter qualification because it is possible, even if human beings become extinct, that human civilization might leave monuments that could be appreciated by other sentient species that could visit the Earth. It is even possible (however unlikely) that other species might appreciate the human record of civilization more than we appreciate it ourselves. Thus human extinction need not mean the loss of human cultural legacy. A pandemic that killed only human beings could have this result. (X marks the spot in the table above.)
4. Human extinction with the extirpation of all human legacy The second level of human extinction I will call compound extinction, which is an existential risk realized that results in human extinction and the elimination of all (or almost all) signs of human presence, but which leaves the biosphere largely intact, and the ordinary business of terrestrial life continues largely unchanged. (This is human extinction coupled with “destruction of cultural heritage.”)
5. Catastrophic compromise of the biosphere The third level of human extinction involves not only the extinction of human beings and all human legacy, but also the extinction of all complex life on the Earth. Terrestrial life continues, but is reduced to single celled organisms. Thus there remains the possibility that life on Earth may recover, but this would probably require billions of years and result in very different life forms.
6. Terrestrial sterilization The most radical form of realized existential risk is terrestrial sterilization which results in human extinction, the extirpation of all human legacy, and the elimination of all terrestrial life, i.e., complete catastrophic failure of the biosphere. From this point there is nothing that can be recovered and no human legacy remains.
I tried to arrange these various morally distinct outcomes on an expanded version of Bostrom’s table of qualitative risk categories, but couldn’t yet find a conceptually neat and straight-forward way to do so. Further thought is needed here. I don’t think there is a need to distinguish further qualitative categories of risk beyond existential risk — in other words, we can refer to all of these morally distinct outcomes as outcomes of existential risk, as realized in distinct scenarios. However, one could make such distinctions if it were helpful to do so.
The most radical moral imperative of existential risk is to take existential risk as absolute and as trumping all other concerns, which is what I clearly implied when I wrote that, “…our other ‘priorities’ pale by comparison. Nothing else matters, no matter how apparently pressing…” if we are made (or make ourselves) extinct. This radical position has profound and discomfiting implications.
If we survey the evils of the world, we would be forced to acknowledge that it is better that any or all of these evils continue than that human life should be permanently extinguished, because the continuation of these evils is consistent with the continuation of human life and human civilization. The end of all human life would also mean the end of all the cruelties and inhumanity that we inflict upon our fellow man, and this would be a good and indeed a desirable state of affairs, but from a radical perspective on existential risk we would have to affirm that, as good a state of affairs as this represents, it would not be as morally good as the state of affairs that involves the perpetuation of these evils together with the perpetuation of human life and civilization.
Of course, under most conceivable scenarios there is no reason whatsoever to suppose that we had to choose between the perpetuation of all the evils of the world and human extinction. That is to say, there is no reason that we cannot work toward the elimination of human evils and the mitigation of existential risks. As a moral thought experiment, however, we can employ the method of isolation and ask whether the survival of human beings and human civilization, together with all the evils this entails is better than the annihilation of human beings and human civilization, so that neither human good nor human evil remains.
While I would be willing to assert that existential risk mitigation trumps all other concerns, even in a thought experiment in which human evils remain unmitigated, I can easily imagine that there are many who would disagree with this judgment. Moral diversity is a fact of human life, and we must recognize that if some among us (myself included) would be willing to explicitly affirm the radical moral consequences of prioritizing existential risk mitigation, there will be others who will equally explicitly reject a radical prioritization of existential risk mitigation, and who will affirm that it is better that the world should come to an end than that the manifold evils of our time should persist. From this point of view, in view of the limited resources available to human beings, we would do better to direct these resources to the mitigation of human evils than to direct these resources to the mitigation of existential risk.
It is entirely possible that someone might affirm that it is a good thing civilization should be ended, and the idea has incredible romantic appeal that cannot be denied and should not be ignored. Many are the science fiction books and films (for example, think of Logan’s Run or 12 Monkeys) that depict a world empty of human beings and populated only by collapsing buildings and animals hunting in the ruins. This scenario is depicted, for example, in Alan Weisman’s book The World Without Us.
The idea that civilization is evil can easily be extended to the idea that humanity is evil in and of itself. The predictions of the original Club of Rome report of 1972, The Limits to Growth, have been widely discussed on its recent 40th anniversary, but what has not been remarked is the language and tone of that original document (which you will not find on the internet, despite the millions of used copies kicking around). The report boldly asserted, “The earth has cancer and the cancer is Man.” This kind of rhetoric, which is less common today, can easily play into a principled denial of the moral value of humanity.
And it is easy to understand why. The world is filled with evils, and the most horrific evils are those that human beings perpetrate upon other human beings — homo homini lupus. If we prioritize existential risk mitigation over the mitigation of human evils, we find ourselves forced into the uncomfortable position of tolerating Kantian radical evil, Marilyn McCord Adams’ conception of horrendous evils, and Claudia Card’s atrocities. Imagine the horrors of genocide, torture, and industrialized warfare and then imagine being forced to admit that it is better than genocides occur, better that torture continues, and better that industrialized warfare persists than that an existential risk be realized. This is a hard saying; nevertheless, this is the argument that must be made, and it is always best to face a hard argument directly than to attempt to avoid it.
In Marilyn McCord Adams’ exposition of what she calls “horrendous evils” in her book Horrendous Evils and the Goodness of God Adams wrote:
“Among the evils that infect this world, some are worse than others. I want to try to capture the most pernicious of them within the category of horrendous evils, which I define (for present purposes) as ‘evils the participation in which (that is, the doing or suffering of which) constitutes prima facie reason to doubt whether the participant’s life could (given their inclusion in it) be a great good to him/her on the whole.’ The class of paradigm horrors includes both individual and massive collective suffering…”
Marilyn McCord Adams, Horrendous Evils and the Goodness of God, Ithica: Cornell University Press, 1999, p. 26.
She went on to add in the next section:
“I believe most people would agree that such evils as listed above constitute reason to doubt whether the participants’ life can be world living, because it is so difficult humanly to conceive how such evils could be overcome.”
In the last paragraph of her paper of the same title, Adams again suggests that horrendous evils call into question the possibility of having a life worth living:
“I would go one step further: assuming the pragmatic and/or moral (I would prefer to say, broadly speaking, religious) importance of believing that (one’s own) human life is worth living, the ability of Christianity to exhibit how this could be so despite human vulnerability to horrendous evil, constitutes a pragmatic/moral/religious consideration in its favour, relative to value schemes that do not.”
Marilyn McCord Adams, “Horrendous Evils and the Goodness of God.” Anthologized in The Problem of Evil, edited by Marilyn McCord Adams and Robert Merrihew Adams, Oxford: Oxford University Press, 1990, p. 221.
A generalization of Adams’ argument could easily bring us from the point where horrendous evils make the individual doubt or question that one’s life is worth living to the point where humanity on the whole legitimately, and on principle, questions whether any human life at all is worth living. If humanity comes to decide that horrendous evils overwhelm all value in the world and make human existence utterly meaningless and pointless, then the mitigation of existential risk can come to seem like an evil or an impiety.
Adams finds her answer to this in Christianity; we naturalists cannot appeal to supernaturalistic validation or justification: we must take human evil on its face along with human good, and if we prioritize the mitigation of existential risk (and therefore the continuity of humanity and human civilization), we do so knowing that human evils will continue and are probably ineradicable if not inseparable from human history.
We can actively seek to mitigate human evils, and the effort has intrinsic value, but the intrinsic value of the mitigation of suffering and mundane meliorism can only continue in the case that humanity and organized human activity continue. Therefore the prioritization of the mitigation of existential risk is what makes possible the realization of the intrinsic value of the mitigation of suffering and efforts toward meliorism. With the end of humanity would also come not only an end to all intrinsic goods of human life, but also an end to the intrinsic good of the mitigation of suffering and the effort to make the world a better place.
We can only create a better civilization if civilization continues. If we are perfectibilists, we may believe in the perfectibility of man and indeed even the perfectibility of civilization. This project cannot even be undertaken if humanity and human civilization are cut short in their imperfect state.
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Existential Risk: The Philosophy of Human Survival
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